3. Expansion, Conflict & the Civil War Era 1800-1865

After 1800, the young United States grew rapidly westward. The Louisiana Purchase (1803) -- when President Thomas Jefferson bought a vast territory from France -- roughly doubled the nation's size. The idea that the U.S. was destined to stretch from coast to coast became known as Manifest Destiny.

Expansion, however, raised a question that could not be avoided: would new territories allow slavery? The country was already deeply divided:

• The South relied on enslaved labor for cotton plantations and wanted to extend slavery.
• The North was industrialising and increasingly opposed to slavery's spread.
• A series of compromises -- the Missouri Compromise (1820), the Compromise of 1850, and the Kansas-Nebraska Act (1854) -- temporarily patched the divide but settled nothing.

The Dred Scott decision (1857) by the Supreme Court ruled that enslaved people were property, not citizens -- enraging the North. The election of Abraham Lincoln in 1860, on a platform opposing slavery's spread, triggered Southern secession. Eleven southern states formed the Confederate States of America, and the Civil War began in April 1861 when Confederate forces fired on Fort Sumter.

Key Civil War developments:

• Emancipation Proclamation (January 1, 1863) -- Lincoln declared enslaved people in Confederate states to be free, turning the war into an explicit fight to end slavery.
• Battle of Gettysburg (July 1863) -- the bloodiest battle of the war; the Union's victory stopped the Confederate advance into the North.
• Gettysburg Address (November 1863) -- Lincoln's short, powerful speech redefined the war as a struggle for equality and democracy.
• The Confederacy surrendered in April 1865; Lincoln was assassinated days later.

⚠️ Common misconception: the Civil War was caused by multiple factors -- slavery, states' rights, economic differences -- but the GED® recognises slavery as the central cause. The Emancipation Proclamation did not immediately free all enslaved people; it applied only to Confederate states.

💡 Tip: trace the sequence -- Manifest Destiny -> slavery debate -> failed compromises -> election of Lincoln -> secession -> war. Understanding WHY something happened earns more GED® points than memorising exact dates.